From the state of the art is known of transmission shift systems for idler wheels. In the familiar transmission shift systems, generally, synchronizing devices are provided for the purpose of synchronizing the idler wheels, wherein the devices mechanically actuate the sliding sleeves in order to synchronize the desired idler wheel with a shaft. This way the necessary torque is transmitted from the idler wheel to the shaft or vice versa.
Generally, a displaceable sliding sleeve is used as the shifting element, having an appropriate profile, which slides onto the profile of the counter-piece upon actuation. For this, it is required that the normally existing RPM differential between the idler wheel and the shaft first assumes the value zero. Otherwise, it is not possible to connect the two profiles without resulting in undesirable grating in the transmission. Accordingly, the two profiles should only come into contact with each other when the rotational speeds between the idler wheel to be shifted and the shaft have been balanced. Therefore, a locking synchronizing device is provided, which prevents early shifting through a mechanical locking device.
The publication DE 37 11 490 C2 discloses a gear shifting device. In this gear shifting device, the sliding sleeve is actuated by an adjusting arrangement accommodated in the shaft and operated by means of hydraulic fluid, wherein the arrangement consists of a hydraulically actuatable piston arrangement. A connecting pin, which connects the sliding sleeve with the hydraulic piston arrangement, is provided, which extends through a hole with axial play that is arranged transversely in the shaft. The familiar gear shifting device disadvantageously requires a very complex layout, since the actuating device or piston arrangement is accommodated in the gear shaft. This affects the manufacturing costs of the familiar gear shifting devices negatively.
From the publication GB 2 214 248 A is known of a gear ratio selection mechanism for a motor vehicle transmission. The mechanism utilizes fluid-operated actuators and an electro-hydraulic driver. With a first actuator the desired gear ratio is selected and, with a second actuator, a movement in the direction of the neutral path is enabled, wherein the first actuator activates a desired gear ratio by moving transversely to the neutral path. Furthermore, potentiometers are provided, which allow the respective positions of the actuators to be determined and be passed on to a control system in the form of signals.
It is the object of the present invention to suggest a transmission shift system of the aforementioned kind, which comprises a synchronization device with a simple design of which easy and also secure synchronization can be achieved.